It tests perfect on the lab.... but as we all know....
Full speed, no CRC or any other type of errors. Long cables, short cables
etc etc.
I generally only hear from cambium users. And not that much, so it is not
happening on all of them, but some.
I do have 3 components coming that have better specs that I am switching
to.
It will improve NEXT and return loss.
If that is the cause then that will be the fix.
There is also a thing in the POE inserters called the "Bob Smith" or BS
termination.
There really was a guy named Bob Smith that did the original calculation.
There is another guy that has more recently published a different
mathematical treatment of the BS termination that uses a different
impedance. I am going to try this and see if it improves things as well.
-----Original Message-----
From: George Skorup
Sent: Saturday, July 29, 2017 4:10 PM
To: af@afmug.com
Subject: Re: [AFMUG] new GigE-APC issues
I had very few issues with the previous ones. The RJ45 tab facing at the
PCB was a minor inconvenience. Sync over power + gigabit didn't play
nice with those, but GigE otherwise worked fine.
I tested a couple prototypes of the new revision for Chuck. Sync over
power + gigabit with a PowerInjector+Sync and a 450 AP worked fine. Then
we replaced that AP with a 450i because of the 450's PPS limit. I didn't
notice it at the time, but the 450i never came up at gigabit. We didn't
really need >80Mbps downlink anyway. It would usually run about 55-60 at
night which was where the 450 was crapping out. Well, more like 50 and
9-10k PPS.
Now I've got some ePMP GPS radios for PTP (not for sync, just the GigE
interface). Same symptoms as the UBNT prism thingamajig. The link comes
up at gig, but flaps and constant FCS errors. The 450i just goes, gig,
gig, gig, nope.. 100mbps at bootup.
Pulling the SS out makes it work, but I can't do that. We lost that 450i
AP because someone went and bypassed the SS because they were apparently
concerned about the CRC errors and didn't f'ing tell me about it, even
after I said I'd debug it on Monday. Welp, a storm rolled in the Friday
before and.. there went the AP. Good job! In Steve Jones' words, I have
only one comment: fuckwits.
I'd say just stay tuned. Chuck is working on it. As he put it, GigE is a
different animal. NEXT, FEXT and all that fun stuff.
On 7/29/2017 4:20 PM, Matt wrote:
Seeing same issues on Gigabit ethernet ports with Cambium PxP450i and
also SAF licensed gear. Shorter cable runs help but just not possible
on some towers. Bypassing the GigE-APC always fixes it.
On Sat, Jul 29, 2017 at 12:40 PM, George Skorup
<george.sko...@cbcast.com> wrote:
I think I've seen this mentioned a few times now. Maybe Steve and a
couple
others?
The latest revision (D?) is causing CRC/FCS errors and random link drops.
Taking the SS out makes all problems go away.
Definitely more issues at gigabit. I have multiple sites with some UBNT
and
ePMP stuff (no sync over power). Some I've turned off gigabit negotiation
and get only a few FCS errors here and there. Running gigabit sees lots
more
errors and adds a 2-3 second link loss randomly which is a big issue on a
PTP link.
Got a couple sites with 450i APs. One that I was working with the other
day
is a new radio (because the old one blew up). New cable, new GigE-APC,
new
PacketFlux PowerInjector. The link tries to negotiate gigabit, but falls
back to 100 after a few tries. Turned off sync over power just to see and
still no gigabit. Remove the SS and it works fine.
Floating the shield makes no difference. Running the site on battery also
makes no difference. Some FM sites, some water towers, some elevators,
some
regular towers with only our stuff on it.
The stuff I was working with yesterday is a new UBNT Prism PTP radio, new
GigE-APC, new CCR1009. This site also has an Exalt G2-11 fed by an older
GigE-POE-APC and I get no errors on that. It used to be plugged into a
MikroTik CRS210 and I didn't see any errors on that either.
I had far fewer issues with the older cards. Unfortunately I don't think
I
have any good ones left to do a comparison. I do have a couple that got
some
water in the jack, maybe I can clean those up for testing. I've used
maybe
10 of the new ones now and they all seem to be causing issues. And before
you ask, yes, I've tried dumb gigabit switches at a few sites temporarily
and still see the random link loss with the SS in line.
